This invention relates to engine exhaust driven turbochargers and more particularly to support means or mounting apparatus for a turbocharger that accommodates thermal expansion and contraction of the exhaust duct or body of the turbine portion of the turbocharger.
It is known in the art to provide an engine turbocharger with mounting apparatus or support means for mounting the turbocharger to the engine or another base in a manner that allows thermal expansion and contraction of the exhaust duct or housing of the turbine portion of the turbocharger while minimizing stresses in the turbocharger, mounting apparatus and associated base or support due to the substantial thermal changes. In larger diesel engines, such as locomotive engines where high exhaust temperatures are encountered and the mass of the turbocharger housing or exhaust duct is relatively large, the amount of thermal growth of the exhaust duct or related housing can be significant and involve substantial radial and axial growth of the structure. It is thus desired to accommodate this radial and axial growth in the exhaust duct of an engine turbocharger by providing a relatively simple but effective mounting apparatus which accommodates both radial and axial expansion of the exhaust duct without causing excessive stresses in the exhaust duct, the mounting apparatus or the supporting base.
The present invention provides a mounting apparatus that comprises a rotor support which carries a major portion of the mass of the turbocharger including the rotor bearings and associated rotor and the air compressor ducting as well as a compressor end of the turbocharger exhaust duct. The rotor support is fixed solidly to a mounting base such as the engine or a component thereof. An axially opposite turbine end of the exhaust duct is secondarily supported by support means including a pair of laterally spaced support legs having feet which are fixed to the base. The legs extend upward on opposite sides of the axis to connect with the exhaust duct, or a duct support, at points above the axis of the rotor and associated ducting. The legs are made essentially rigid in resisting vertical forces, but relatively resilient as to axial and radial forces so as to allow axial and radial expansion and contraction of the turbine end of the exhaust duct relative to the compressor end without introducing high stresses in the exhaust duct, the mounting means or the associated support base. Preferably, the points at which the legs are connected with the exhaust duct support are at selected points above the axis where vertical expansion of the exhaust housing between the axis and the connection with the legs approximately equals linear expansion of the legs. Thus, vertical movements of the axis due to thermal changes will be minimized or will approximately equal the position of the axis at the opposite end of the rotor. In this way, the components are maintained in axial alignment without tilting of the axis or misalignment of the structure due to thermal expansion and contraction conditions.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.